The invention relates to marine drives with submerged exhaust outlets, and more particularly to anti-ingestion systems for preventing ingestion of water into the marine drive internal combustion engine after turn-off.
Various types of marine drives have an internal combustion engine having an exhaust system, and a cooling system drawing cooling water from the body of water in which the marine drive is operating. The exhaust system may discharge engine exhaust through the drive and through the propeller. After turn-off of the engine, and upon cool down of the exhaust gas that is trapped between the engine combustion chamber and the submerged exhaust outlet through the propeller, e.g. 10 to 20 minutes, a vacuum may be created in the exhaust system which may draw water back into the engine, which is deleterious to the engine. This water may cause hydrolock upon attempted re-start of the engine, or cause corrosion on an exhaust valve, leading to engine durability issues, or damage emissions compliance hardware.
The present invention arose during continuing development efforts in the above technology.